Time delay circuits



Jan. 7,` 1964 R. M. HUBBARD TIME DELAY CIRUITS Filed July 22, 1959 2Sheets-Sheet 1 IN V EN TOR. ,Palmer f4. #MK/:e0

A r fof/WF? Jan. 7, 1964 R. M. HUBBARD 3,117,234

i TIME DELAY CIRUITs Filed July 22, 1959 2 sheets-sheet 2 @055er M.#UKE/:KP BY A r ro/ew'y g?. l INVENTOR.

United States Patent O This invention relates to electrical time-delaycircuits and more particularly to time-delay circuits of the magnetictype. o "ille subject application is related to patent applications hos.828,749, now Patent No. 3,002,145, and 02m/.50., now abandoned, entitledFull-Wave Magnetic Amphers and Magnetic Amplifiers, respectively, andiiled even date herewith by Robert ivi. Hubbard.

A number of time-delay circuits of the magnetic type are now inexistence. However, these prior art timedelay circuits have certaindisadvantages. For instance, many ol' these time-delay circuits requirea multiple winding transformer for supplying power to the time-delaycircuit. in addition, often times biasing is required for each stage ofthe time-delay circuit, thereby rendering the time-delay circuitsusceptible to drift. Further, in many o these prior art time-delaycircuits, the output from each is dependent upon the magnitude of thesupply voltage for the time-delay circuit. Thus the magnitude orc theoutput voltage from each stage varies in accordance with the magnitudeof the supply voltage. Thus, these disadvantages are such as to effectthe drift characteristics, complexity, and cost of the time-delaycircuit.

Therefore, an object of this invention is to provide for simplifying amagnetic type time-delay circuit by connecting the reset circuit of eachsuccessive stage in parallel circuit relationship with the gate circuitof the previous stage. y

Another object of this invention is to provide a multistage magnetictype time-delay circuit in which a single supply source without amultiple winding transformer is utilised for supplying all of the supplypower to the time-delay circuit.

A further object of this invention is to provide for eliminating biasingon all but the first stage of a multistage magnetic time-delay circuit,thereby simplifying and improving the drift characteristics of thetime-delay circuit.

Still another object of this invention is to provide for rendering theoutput of each stage of a magnetic type time-delay circuit substantiallyindependent of the magnitude of the supply voltage for the time-delaycircuit.

Other objects of this invention will become apparent from tire followingdescription when taken in conjunction with the accompanying drawings inwhich:

PEG. l is a schematic diagram of a single-ended multistage magnetictime-delay circuit embodying teachings of this invention;

2 is a multi-stage magnetic type time-delay circuit embodying furtherteachings of this invention in which the time-delay circuit is adaptedto be controlled by a diiiierential control Voltage and a single windingis provided on each of the magnetic core members of the timedelaycircuit for effecting both gating and resetting of the magnetic coremember;

HG. 3 is a schematic diagram of a magnetic type timedelay circuitsimilar to that of FIG. 2 except that a separate winding is provided oneach of the magnetic core members for effecting a gating and resettingof the magnetic core member; and

HG. 4 is a schematic diagram of a magnetic timedelay circuit similar tothat illustrated in FlG. 2 except that the time-delay circuit of FIG. 4is adapted to have "ice another control signal introduced between therst and second stage.

Referring to FIG. 1 there is illustrated a magnetic type time-delaycircuit lil embodying teachings oi this invention in which thetime-delay circuit i@ is adapted to be connected to supply terminals l2and 12;' which are disposed to be connected to a source i3 ofalternating voltage. Control terminals la and ltd are disposed to beconnected to a source l5, the polarity of whose output voitage is asindicated in FEGURE l. However, for a dilerent type of operation thanthat described hereinafter, the polarity of the control source l5 can bereversed from that shown in FlG. l. ln practice, the source l5 shouldhave sufficient internal impedance to limit the ilow of current fromsource 13 through the source l5.

In general, the time-delay circuit l@ comprises three stages lo, i3 and20. In this instance, the stages 16, l and 2@ comprise magnetic coremembers 22, 24 and 26, respectively, and windings 2S, 3@ and 32 disposedin inductive relationship with their respective magnetic core members22, 24 and 26. Stages 16 and 2@ are gated while stage lh is being reset.When stage I3 is gated, stages lr6 and 2t) are being reset. It is commonfor ease of description to refer to gating orc a core to positivesaturation and then resetting the core away from positive saturationtoward negative saturation. However, this is just a matter of choice,and one could refer to gating a core to negative saturation and theresetting the core toward positive saturation.

accordance with this invention, a current-limiting resistor 34, and aparallel circuit is connected in series circuit relationship withrespect to the source l?. As illustrated, one branch oi the parallelcircuit 36 includes the winding Ztl and a rectiier 33 and the otherbranch or" the parallel circuit 36 includes the winding 3d and arectiier lil?. The rectifiers 38 and d@ are so poled as to permit, onlyduring alternate half-cycles of the output of the source i3 when thesupply terminal l2 is at a positive polarity with respect to the supplyterminal l2, the flow of current from the supply terminal l2 throughboth branches of the parallel circuit 36, and the current-limitingresistor 35i, to the supply terminal l2, to thereby eliect a gating ofthe magnetic core member 22 and a resetting of the magnetic core memberZd during this portion of the operation. In like manner, acurrentlimiting resistor i2 and a parallel circuit ifi is connected inseries circuit relationship with respect to the source i3. As shown, onebranch oi the parallel circuit i4 includes the winding 3@ and arectifier in and the other branch of the parallel circuit le includesthe winding 32 and a rectiiier d8. in this instance, the rectiiiers 46and are so poled as to permit, only during those other alternatehalf-cycles of the output of the source i3 when the supply terminal rZis at a positive polarity with respect to the supply terminal l2', theilow of current from the supply terminal )l2 through the currentlimitingresistor d2, and both branches oi the parallel circuit 414, to thesupply terminal l2', to thereby effect a gating of the magnetic coremember 2d and a resetting of the magnetic core member 26 during thesealternate halfcycles of the operation.

In order to eiiect a gating of the magnetic core member Z6, when thesupply terminal l2 is at a positive polarity with respect to the supplyterminal 12., circuit means Sil is provided. As shown, the circuit means59 includes a rectifier 52 and a current-limiting resistor 54; thewinding 32, the rectifier 52, and the current-limiting resistor Ellbeingconnected in series circuit relationship with respect to the source i3.in operation, the rectiiier 27; functions to block the flow of currentthrough the current-limiting resistor 5f:- when the supply terminal l2is at a positive polarity with respect to the sup-ply terminal l2. Onthe other hand, the current-limiting resister limits the flow of currentthrough the Winding 32 when the magnetic core member 26 is saturated. Inlike manner, the current-limiting resistors 34 and d2 limit the ilow ofcurrent through the windings 2? and 3d when their respective magneticcore members 22 and Z4 are saturated.

For the purpose ot effecting a biasing of each of the magnetic coremembers 22, 24 and 26, an adjustable biasing resistor 56 is connected inseries circuit relationship with a rectifier 58 arid with the WindingZS, the series circuit being connected to the source i3 of alternatingsupply voltage. ln operation, the rectier 5S functions to prevent theilow of current through the biasing resistor S6 when the supply terminall2 is at a positive polarity with respect to the supply terminal l2. Asillustrated, the control source l5 is connected to the winding throughthe rectilier 5S and a movable tap S9 which is disposed to be actuatedalong the Winding to thus provide for higher gain in the stage le? whenthe tap 59 is disposed in a position lower than that shown.

In order to obtain a voltage across a load that is proportional to thevoltage across the Winding 23 when the magnetic core member 22 is beinggated, the load o@ is connected in series circuit relationship with loadterminals 62 and 62 and with a rectier 64 which functions to blocl; tieflow of current through the load d@ when the magetic core member 22. isbeing reset to a given flux level. ln like manner, in order to obtain avoltage across a load ou in accordance with the voltage appearing acrossthe Winding 3i) when the magnetic core member Z4 is being gated, theload 66 is connected in series circuit relationship with respect to loadterminals da and 63 and with respect to a rectifier 7l) which functionsto prevent the flow of current through the load 66 when the magneticcore member is being reset to a given ilux level. Similarly, for thepurpose of obtaining a voltage across a load 72 that is proportional tothe magnitude orr the voltage appearing across the Winding 32 when themagnetic core member 26 is being gated, the load 72 is connected inseries circuit relationship with respect to load terminals '7d and 'i4'and with respect to a rectiier 75 which functions to prevent the iiow ofcurrent through the load 72 when the magnetic core member 26 is beingreset.

The operation of the time-delay circuit itl will now be described.Assuming the supply terminal l2 is at a positive polarity with respectto the supply terminal l2' biasing current ilows from the supplyterminal l2 through the biasing resistor S6, the rectifier 5S in theforward direction, and the winding 2S, to the supply terminal lil', tothus effect a bias of the magnetic core member' 22 in accordance withthe setting of the adjustable biasing resistor 5o' and in accordancewith the magnitude of the supply voltage of the source '13. The iluxlevel in the magnetic core member 22 is also set to a level inaccordance with the magnitude of the direct-current control voltageappearing across the control terminals le and ld. ln operation, controlcurrent ilows, when the supply terminal l?. is at a positive polaritywith respect to the supply terminal l2', from the control terminal 14through the rectifier 5b?, and the winding 28, to the control terminallll.

During the next halt-cycle of operation, when the supply terminal 2 isat a positive polarity with respect to the supply terminal l2, currentiiows from the supply terminal l2 through both branches of the parallelcircuit 36, and the current-limiting resistor 3d, to the supply terminall2, to thereby etifect a gating of the magnetic core member 22 andresetting of the magnetic core member lt is to be noted that themagnetic core member 2d is being reset until the magnetic core member isdriven to saturation, and therefore the amount that the magnetic coremember is reset is in proportion to both the magnitude of the biasingcurrent and control current that tlowed through the Winding Z55 duringthe previous halt-cycle of operation. Thus, the sources i3 and fc5etlect both biasing and control of the magnetic core member 7,4.Simultaneously, during this half-cycle et operation, current flowsthrough the load oil and the rectier 6d, in the forward direction, tothereby eitect a voltage across the load 6d in accordance with thevoltage across the winding 28 during this half-cycle or operation.

During the next half-cycle of operation, when the supply terminal l2 isat a positive polarity with respect to the supply terminal l2', currentllows from the supply terminal l2 through the current-limiting resistord?, and both branches of the parallel circuit 41%, to the supplyterminal l2', to thus eiiect a gating of the magnetic core ember 2d anda resetting of the magnetic core member 2o in accordance with thebiasing and control current that previously flowed through the winding22. At the same time, current llows through the rectifier 7d, and theload 66, to thereby etiect a voltage across the load do in accordancewith the voltage appearing across the Winding 3@ during this latterhalf-cycle of operation.

During the next halt-cycle of operation, when the supply terminal 12 isagain at a positive polarity with respect to the supply terminal l2,current Llows from the supply terminal Z through the Winding 32, therectifier 52 in the forward direction, and the current-limiting resistor5d, to the supply terminal l2, to thus eicct a gating of the magneticcore member Simultaneously, current flows through the load 72, and therectiier ZF6, in the forward direction, to thereby eiect a voltageacross the load 72 in accordance with the magnitude ol the voltageacross the winding 32 during this latter half-cycle of operation. Thus,it can be realized that each of the stages lo, i8 and Z@ iiects a delayin the control current applied to the time-delay circuit lil, however,the magnitude of the voltage appearing across the load T2, of the stage2t), is still proportional to the magnitude of the control voltageappearing acrosss the control terminals ld and ld'.

Referring to FIG. 2 there is illustrated a magnetic time-delay circuit@El embodying further teachings of this invention in which thetime-delay circuit 8l) is adapted to be controlled from a source S2 ofdirect-current differential control voltage. Like components of FIGS. land 2 have been given the same reference characters. ln addition, sincethe timedelay circuit d@ of FIG. 2 comprises two of the time-delaycircuits l@ of FlG. l connected in push-pull operation, the upperportion of the time-delay circuit @il has been given the same referencecharacters as the time-delay circuit lil of FlG. l, and the lowerportion o the time-delay circuit has also been given the same referencecharacters except that they are primed.

The time-delay circuit Sil is also a three-stage timedelay circuit andcomprises stages 8d, 86 and 33. As illustrated, the stage 3d includesmagnetic core members 22 and 22', the stage 86 the magnetic core members2d and 2d and the stage S8 the magnetic core members 26 and 26. Asexplained in connection with FIG. l, the cores on the lett and right inthe circuitry of PIG. 2 are gated While the center cores are beingreset, and visa versa. This is also true with the circuitry shown in theembodiments of FIGS. 3 and 4.

ln order to obtain a voltage at the output of the stage 8d which isproportional to the combined voltage appearing across the windings 2Sand 23', a load @il is conected to load terminals and 92 which areconnected respectively to the junction of the rectiers 33 and fi@ andthe junction of the rectiii rs 3S and dnl. Similarly, in order to obtaina voltage at the output of the stage 86 which is proportional to thecombined voltage appearing across the windings 3@ and 30', a load 9d isconnected to load terminals 96 and 9d which are respectively connectedto the junction point of the rectiliers and.

itl and the junction point of the rectifiers do and 48. ln like manner,in order to obtain a voltage at the output of the last stage 8S which isproportional to the combined voltage appearing across the windings 32and 32' a load 9?, is connected to load terminals ltlt and Mill' whichare respectively connected to the junction point of the rectifier 52 andthe current-limiting resistor and the junction point of the rectifier $2and the current-limiting resistor 54.

The operation of the time-delay circuit S@ of FIG. 2 will now bedescribed. Assuming the supply terminal i2 is at a positive polaritywith respect to the supply terminal l2', biasing current llows from thesupply terminal l2 through the biasing resistor 56, the rectifier S8 inthe forward direction, and the winding 28, to the supply terminal l2',to thus effect a biasing of the magnetic core member 22 in accordancewith the setting of the biasing resistor Simultaneously, biasing currentflows from the supply terminal l2 through the biasing resistor E56', therectiiier 58' in the forward direction, and the winding 23', to thesupply terminal l2', to thereby eiiect a biasing of the magnetic coremember 22 in accordance with the setting of the biasing resistor 5e.Assuming the output of the control source 82. is such as to rendercontrol terminal m2 at a positive polarity with respect to controlterminal itil', control current at the same time flows from the controlterminal llZ through the rectiiier 5S, the windings 2S and 2h', and therectiiier 33 and the resistors and Se', to the control terminal M2', tothereby set the ilux level in the magnetic core members 22 and 22' inaccordance with the magnitude of the output of the control source 82.However, the control current flowing through the winding 28 is additiveto the biasing current iiowing therethrough while the control currentriowing through the winding 28' is subtractive from the biasing currentiiowing through this latter winding. Therefore the magnetic core member22 is set to a iux level further below positive saturation than is themagnetic core member 22.

During the next halt-cycle of operation, when the supply terminal l2' isat a positive polarity with respect to the supply terminal l2, currentflows from the supply terminal l2 through both branches of the parallelcircuit 36 and the current-limiting resistor Tall, to the supplyterminal l2, to thus effect a gating of the magnetic core member 22 anda resetting of the magnetic core member 2&2, in accordance with thevalue to which the magnetic core member 22, had been reset during theprevious half-cycle ot operation. At the same time, current tlows fromthe supply terminal l2' through both branches of the parallel circuit3s', and the current-limiting resistor 34', to the supply terminal l2,to thereby elect a gating of the magnetic core member 22 and a resettingof the magnetic core member 2.4L', in accordance with the iiux evel towhich the magnetic core member Z2 had been reset during the previous1nali-cycle of operation. lt is to be noted that during this half-cycleof operation, when the supply terminal l2' is at a positive polaritywith respect to the supply terminal l2, the magnetic core member 22'saturates first under the assumed conditions and until this time ofsaturation the voltage across the windings 2S and 28 are substantiallyequal and therefore substantially no voltage appears across the load 90.

lowever, once the magnetic core member 22 saturates,

the voltage across the winding 28 appears across the load 9@ until themagnetic core member 22 saturates, and the polarity of this voltageacross the load 9u is such that the load terminal 92' is positive withrespect to the load terminal 92. Gf course, when both the magnetic coremembers 22 and 22' become saturated, substantially no voltage appearsacross the load li.

During the next half-cycle of operation, when the supply terminal l2 isagain at a positive polarity with respect to the supply terminal l2',current iiows from the supply terminal l2 through the current-limitingresistor 42 and both branches of the parallel circuit d4, to the supplyterminal 12', to thereby eiiect a gating of the magnetic core member 2dand a resetting of the magnetic core member Z6 in accordance with theiiux level to which the magnetic core member 2.4i had been reset duringthe previous halt-cycle of operation. Simultaneously, current tlows fromthe supply terminal l2 through the current-limiting resistor d2', andboth branches of the parallel circuit 44' to the supply terminal l2 tothus eiiect a gating of the magnetic core member 2d' and a resetting ofthe magnetic core member 2e' in accordance with the flux level to whichthe magnetic core member 24' had been reset during the previoushalf-cycle of operation. Here again, no voltage appears across the load9d until the magnetic core member 2li' saturates. Once the magnetic coremember 24' saturates, a voltage appears across the load 94 of suchpolarity that the load terminal 5o is at a positive polarity withrespect to the load terminal 96. Then when the magnetic core member Zitsaturates, substantially no voltage appears across the load 94.

`7i/hen the supply terminal l2 again becomes positive with respect tothe supply terminal l2, current flows from the supply terminal l2through the winding 32, the rectifier 52 in the forward direction, andthe current-limiting resistor dit, to the supply terminal l2, to thusgate the magnetic core member 26. At the same time, current iiows fromthe supply terminal L.' through t Ae winding 32', the rectifier 52 inthe orward direction, and the currentlimiting resistor 54', to thesupply terminal l2, to thereby gate the magnetic core member 2e'. Untilthe magnetic core member '26' saturates, the voltages across thewindings 32 and 32 are of substantially equal value and thereforesubstantially no voltage appears across the load it. However, once themagnetic core member 2.6' saturates, a voltage appears across the loadof such polarity that the load terminal itil" becomes positive withrespect to the load terminal llhl. Then when the magnetic core member 26saturates substantially no voltage appears across the load 98.

lf the polarity of the output voltage of the control source 2 reversesso that the control terminal M2 is at a positive polarity with respectto the control terminal M52, control current tlows, during thehalf-cycle ot operation when the supply terminal l2 is at a positivepolarity with respect to the supply terminal l2', from the controlterminal 162', `through the rectifier 53', the windings 28 and 23, andthe rectiiier and the resistors and 5o, to the control terminal M92. lnthis case, the control current owing through the winding Z3 is additive`to the biasing current tiowing therethrough and the control currentflowing through the winding Ztl is snbtractive from the biasing currentllos-ving through this latter winding, and therefore the magnetic coremember 2.2 is set to a l'lux level further away from positive saturationthan is the magnetic core member 22. rl`hus, the magnetic core members22, 2li and 2d saturate before their respective magnetic core members22', 2%" and 25. rthe remaining operation of the time-delay circuit Stiis similar to that previously described when it was assumed that thecontrol terminal i652 was at a positive polarity with respect to thecontrol terminal MZ except that the voltages obtained across the loadstill, and @l5 are of reverse polarity.

Referring to FlG. 3 there is illustrated a magnetic type time-delaycircuit itl-tf similar to that of FlG. 2 except that a separate windingis provided on each of the magnetic core members for effecting a gatingand a resetting of the respective magnetic core members. The time-delaycircuit ltl/i is adapted to be connected to a source lilo of alternatingsupply voltage, the source being connected to supply terminals andlll-li'. The control signal for the time-delay circuit Ich@ is receivedfrom a direct-current differential control source il@ which is connectedto control terminals lf2 and lllj'. ln general, the timedelay circuitles; comprises three stages, llt, lla and lllS which in turn includemagnetic core members l2@ and 122, E24 and l26, and and i3d,respectively. Each of the iagnetie core members liti, T172, E24, 126,i125 and 13@ have disposed in inductive relationship therewith aseparate gate winding and a separate reset winding, speciiically, gatewindings T132., "34, E33, li/'itl and MZ, respectively, and resetwindings Me, ifi-6, ll, lltl, 152, and ld, respectively.

in accordance with this invention, a current-limiting resistor ido and aparallel circuit is connected in series circuit relationship withrespect to the supply source one branch of the parallel circuit lSincluding a rectifier' and the gate winding Jil and the other branch ofthe parallel circuit including a rectilier M2 and the reset winding lnpractice, the rectiiiers tot? and loll are so poled as to permit, onlyduring the alternate halfcycles of the output of the source when thesupply terminal lil is at a positive polarity with respect to the supplyterminal lifts, the tlow of current from the supply terminal w3 throughboth branches of the parallel circuit and the current-limiting resistor156, to the supply terminal ln like manner, a parallel circuit lofi anda currentlirniting resistor lle-6 are connected series circuitrelationsi ip with respect to the source one branch of the parallelcircuit lo@ including a rcctiner L63 and the gate winding i341- and theother branch of the parallel circuit lied including a rectiiier i7@ andthe reset winding ltStl. l'n lthis case, the rectiiiers and 17o are sopoled as to permit, only during the lternate halt-cycles of the outputot the source when the supply terminal ltll is positive with respect tothe supply terminal 168, the flow of current from the supply terminali533 through both branches of the parallel circuit Mi i, and thecurrentlimiting resistor M6, to the supply terminal lltll.

ln order to obtain a voltage at the output of the stage that isproportional to the combined voltage appearing across the gate windingsi3?, and r3/l during the alternate halt-cycles of operation when thesupply terminal ltl is at a positive polarity with respect to the supplyterminal a load 72 is connected to load terminals ,E7-- and Uli with theload terminal 1174 connected to the junction point of rectifiers le@ andlie and with the load terminal lilconnected to the junction point of therectilicrs 16S and HG.

Also in accordance with this invention, a current-limiting resistor ll'oand a parallel circuit l is connected in s ries circuit relationshipwith respect to the supply source iti-6, one branch of the parallelcircuit l including a rectifier and the gate winding E36, and the otherbranch of the parallel circuit inclu-ding a rec'qer 1&2 and the resetwinding if ln this instance, the rectiiers l@ and are so polcd as topermit, only during the other alternate halt-cycles of the output of thesource lilo when the supply term l 1% is at a positive polarity withrespect to the supply terninal 19S', the flow ot current from the supplytern .al itt-3 t; rough the current-limiting resistor 176 and bothbranches of the parallel circuit E78, to the supply terminal it E.

Also in accord nce with this invention, a current-limiting resistor anda parallel circuit we is connected in series circuit relationship withrespect to the supply source fluo, one branch of thc parallel circuitE36 including a rectifier the gate winding l, and the other branch ofthe parallel circuit including a rectier t9@ and the reset Winding Asshown, the rectiers T138 and @il are so poled as to permit, only duringthose alternate halt-cycles ot the output or the supply source titlewhen the supply terminal is at a positive polarity with respect to thesupply term'aal MBS', the flow ot current from the supply terminalthrough the current-limiting resister s and both branches of theparallel circuit ld, to the supply terminal M LUL? ln order to obtain anoutput voltage from the stage that is proportional to the combined voltg ing across the gate windings during the alternate half-cycles ofoperation when the supply terminal 163 is at a positive polarity withrenpcct to supply' terminal MES', a load @E is connected to oadterminals. i9@ and 1%', the load terminal 1% being connected. to thejunction point of the rectiiers itl@ and i152, and the load terminallig/l being connecte to the junction point of the rectilers lh and ld.

For the purpose of effecting a gating of the magnetic core member 32Sduring the alternate half-cycle of operation when the supply terminalECW-2 is at a positive polarity with respect to the supply terminal E63,the gate winding Mil is connected in series circuit relationship with arectier llo and with a current-limiting resistor the series circuitbeing connected across the supply terminals and ln like manner, in orderto etlect a gating of the magnetic core member i3d during the samehalf-cycle of operation the ate Winding isi connected in series circuitrelationship with a rectifier and with a current-limiting resistor 292,the series circuit also being connected across tbe supply terminalsltl'll and lite. In operation, the rectiers En and Zilli function toprevent the ow of current through the gate windings lllii and lift@ whenthe supply terminal lll is at a positive polarity with respect to supplyterminal w8. On the other hand, when the supply terminal Miti' is at apositive polarity with respect to supply terminal MS, thecurrent-limiting resistor 1% functions to limit the liow of currentthrough the gate winding lift@ once the magnetic core member reachessaturation and the current-limiting resistor 2d?. in like mannerfunctions to limit the flow of current through the gate winding M22 whenthe magnetic core member lfsll reaches saturation.

ln order to obtain an output voltage from the output of the stage llltlthat is proportional to the combined voltage appearing across the gatewindings le@ and ifi?. when the magnetic core members lE and i359 arebeing gated, a load Ztl-fl is connected to load terminals 2.96 and 2de',with the load terminal 2% connected to the junction point of therectifier i196 and the current-limiting resistor i455 and with the loadterminal Zilli connected to the junction point of the rectifier Ztl@ andthe current-limiting resistor 202.

Bias for the magnetic core members and L25 is `eilected by connectingthe reset winding le-lt series circuit relationship with a rectifier andwith an adjustable biasing resistor 2li?, the series circuit beingconnected across the supply terminals lila? and 1%. ln like manner,biasing of the magnetic core members i221, E26 and lftl is eiected byconnectin0 the reset winding M6 in series circuit relationship with arectifier El?, and with an adjustable biasing resistor 214, the seriescircuit being connected across the supply terminals llll. ln operation,the rectiers t28 and function to prevent the llow of biasing currentthrough the reset windings lllll and lido, respectively, when 'thesupply terminal Miti is at a positive polarity with respect to thesupply terminal lieti. The magnituce c-t the biasing current flowingtlnough the reset windings E451 and 1546 can be changed by adjusting thebiasing resistors 2l@ and 214, respectively.

The operation of the time-delay circuit lll@ u ill now be described.During the alternate half-cycles of operation when the supply terminalMiti is at a positive polarity with respect to supply terminal lith',biasing current flows from the supply terminal lll@ through the biasingresistor Fill, the rectiiier in the forward direction, and the resetwinding 314543-, to supply terminal lll to thereby' ei'ect a biasing otthe magnetic core membe 12u. in like manner, biasing current iloveduring this same half-cycle of operation from the supply terminal 1%through the biasing resistor 2M, the rectifier 2l?, in the forwarddirection, and the reset winding les, to the nal is at a positivepolarity with respect to the supply terminal he operation of thetime-delay circuit 2l@ will now be described. so is at a positivepolarity with respect to the supply terminal 225', biasing current ilowsfrom the supply terminal 226 through the bi i resistor :56, therectifier in the forward direction, and the winding 23, to the supplyterminal 22o', to thereby bias the core member 22 in accordwith thesetting of the adjustable biasing resistor Se. At the same time, biasingcurrent flows from the supply teuninal tiaough the biasing resistor 56',the rectifier 73' in the forward direction, and the winding 2l', to thes Jply terminal 22o', to thus bias the magnetic core member 22' inaccordance with the setting oi the adiustable bias' resistor 56.practice, the magnetic core members and are b ed an equal amount.

Assuming the polarity oi' the output voltage o the control source issuch that the control terminal i532 is at a positive polarity r lrespect to the control terminal M12' and assuming further dat the outputvoltage of tbe control source 's such that tbe control terminal 22% isat a positive polar: y with respect to the control terminal 22h, controlcurrent flows from the control tern inal lo?. through the rectiiier theu ndings 23 and 2S', and the rectifier Sti', to the control terminalltl2'. Since the control current through the winding Ztl is additive tothe biasing current flowing therethrough and since the control current'ii/owing through the vf ding 23 is subtractive from the biasing currentilowing therethrough, the magnetic core member is reset further awayfrom positive saturation than is the magnetic core member 22.

During the next half-cycle of operation when the supply terminal 226 isat a positive polarity with respect to the supply terminal 22o, currentiiows from the supply -terminal 22o through `the winding 23, therectitier 38 in the forward direction, and the current-limiting resistor34, to the supply terminal 226 to thus effect a gating of the magneticcore member 22. Simultaneously, current lows `from the supply terminal226 through the winding 2S', the rectier 3S in the forward direction,and the current-limiting resistor 34', lto the supply terminal 226, tothereby effect a gating of the magnetic core member 22. However, sincethe magnetic core member 22 under the assumed conditions had been resetto a level further :aw-ay from positive saturation during the previoushalf-cycle of operation than had the magnetic core member 22', themagnetic core member 22' saturates before the magnetic core member 22.Gnce the magnetic core member 22 saturates, a voltage appears across theload Si@ of such polarity that the load terminal 92 is at a positivepolarity with respect to the load terminal 92. Then when the magneticcore member 22 saturates substantially no voltage appears -across theload 9i). However, when a voltage does appear across the load 9b, thisvoltage is additive to the voltage appearing across the controlterminals 22@ and 22h', and this combined voltage eiiccts a resetting ofthe magnetic core members 2d and 2d during this same half-cycle ofoperation when the supply terminal 22o is at a positive polarity withrespect to the supply terminal 226.

At the same time the combined voltage across the load terminals $2 and92 and across the control terminals 22@ vand 22o is effecting aresetting of the magnetic core members 24 and 24K, biasing current isowing from the supply terminal 22E through the winding 3o, the rectier234) in the forward direction, and the biasing resistor 232, to thesupply terminal 223. Simultaneously, biasing current is also iowing fromthe supply terminal 223 through the winding Sil', the rectifier 23d inthe Aforward direction, and the biasing resistor 236, to the supplyterminal Under the assumed conditions, the control current ilowingthrough the winding Sii is subtractive from the biasing current flowingtherethrough and the control current through the winding is additive tothe biasing current llowing through the winding 3G, and therefore themagnetic core member 2li is reset at a further level below positivesaturation than is the magnetic core member 2li'.

During the next halt-cycle of operation, when the supply terminal 22S'is at a positive polarity with respect to the supply terminal 22S,current flows from the supply terminal 22S through the current-limitingresistor 42, and both branches of the parallel circuit 434i, to thesupply terminal 21213, to thereby eiect a gating of the magnetic coremember 24 and a resetting of the magnetic core member 2o in accordancewith the ilux level to which the magnetic core member 24 had been resetduring the previous halt-cycle of operation. At the same time, current'liows from the supply terminal 22o' through the currentlimitingresistor 42', and both branches of the parallel circuit 44X, to thesupply terminal 22S, lto thus effect a gating of the magnetic coremember 2d' and a resetting oi the magnetic core member 26 in accordancewith the "lux level to which the magnetic core member 2d' had been resetduring the previous half-cycle of operation.

Since the magnetic core member 24 had been reset to a linx level furtherbelow positive saturation than the magnetic core member 2d', themagnetic core member 24 saturates first and once it saturates, a voltageappears across the load 9d of such polarity that the load terminal @o isat a positive polarity with respect to the load terminal 96'. Once .themagnetic core member 2d saturates, substantially no voltage `appearsacross the load 9d.

During the next half-cycle of operation, when the supply terminal againis as a positive polarity with respect to the supply terminal 22S',current flows from the supply Iterminal 22S through the winding 32, therectiiier 52 in the forward direction, and the current-limiting resistor54, to the supply terminal 228', to thus eiiect a gating of the magneticcore member 26. Simultaneously, current ows from the supply terminal223` through the winding 32', the rectiiier 52" in the forwarddirection, and the current-limiting resistor 54', to the supply terminal223', to thus effect a gating of the magnetic core member 26'. Duringthis half-cycle of operation, the magnetic core member 26' saturatesfirst, and then a voltage appears `across the load 9@ of such polaritythat the load terminal No is at a positive polarity with respect to theload terminal lilo. This voltage appears across the load 98 until themagnetic core member 26 saturates, and then substantially no voltageappears across the load 98.

lf the polarity of the output voltage of the control source 82 reverses,the polarity of the voltage across the load 9i) also reverses, and thenassuming the same output polarity for the voltage of the source ZES, thevoltage across the control terminals 22@` and 226" is subtractive fromthe voltage across the load 9i?, and this difference in voltage ciects aresetting of the magnetic core members 24 and 24. F.then the polarity ofthe voltages across the loads 94 and 98 is dependent upon whether thevoltage across the load 9u is larger or smaller than the control voltageappearing across the control terminals 22@ and 226.

On the other hand, if the polarity of both the voltages across thecontrol terminals N2 and M12 and across the control terminals 2243' and22u reverses from the condition rst assumed, the voltage across the load9@ is additive to the voltage across the control terminals 22o and 22d',and the polarity or" the voltages across the loads 94' and 9b reversesfrom that polarity obtained under the rst assumed conditions for the twocontrol vol-tages.

lt is to be understood that the reversible polarity directcurrentcontrol sources E2, llt) and 2lb, shown in FiGS. 2 through 4, can bereplaced by a reversible-phase alternating control source (not shown)synchronized with and of the same yfrequency as the supply sourcesassociated with the particular time-delay circuit. lt is also to beunderstood that an alternating control source (not shown) 13 could besubstituted for the direct-current control source l provided thepolarity of the output of the alternating control source (not shown) isthe `same as that of the direct-current control source l5 during therese-t halfcycle of operation when the magnetic core member 22 is beingreset.

The apparatus and circuits embodying the teachings of this inventionhave several advantages. For instance, a single supply source can beutilized for the apparatus and circuits shown in FIG-S. 1 through 3. lnaddition, it is only necessary to provide biasing on the first stage ofthat apparatus and circuits shown in FIGS. 1 through 3. Further, in theapparatus and circuits of FIGS. 1 through 4, the output from each stageis substantially independent of the magnitude of the supply voltage.Also, the apparatus and circuits of FIGS. 1 through 4 are extremelysimple, considering the functions performed, thereby minimizing theoriginal cost of the apparatus.

Since certain changes may be made in the above described apparatus andcircuits and different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

l claim as my invention:

1. ln a magnetic type delay line adapted to be connected to a source ofalternating voltage, the combination comprising, a first magnetic stageincluding magnetic core means having winding means disposed in inductiverelationship therewith, a second magnetic stage including magnetic coremeans having winding means disposed in inductive relationship therewith,circuit means for connecting said winding means of said first stage andsaid winding means of said second stage in parallel circuit relationshipwith respect to one another, currentlimiting means, other circuit meansfor connecting said parallel circuit and said current-limiting means inseries circuit relationship with respect to said source, so that currentis permitted to flow from said source through both said winding means ofsaid first stage and said winding means of said second stage only duringalternate halfcycles of the output of said source to thus gate saidmagnetic core means of said first stage and reset said magnetic coremeans of said second stage, means for resetting the flux level in saidmagnetic core means of said first stage during the other alternatehalf-cycles of the output of said source, still other circuit meansconnected to said source for eilecting a gating of said magnetic coremeans of said second stage during said other alternate half-cycles ofthe output of said source, and further circuit means for connecting aload across said winding means of said second stage.

2. in a magnetic type delay line adapted to be connected to a source oialternating voltage, the combination comprising, a rst magnetic stageincluding a magnetic core member having a winding disposed in inductiverelationship therewith, a second magnetic stage including a magneticcore member having a winding disposed in inductive relationshiptherewith, a third magnetic stage including a magnetic core memberhaving a winding disposed in inductive relationship therewith, aparallel circuit, one branch of which includes a tirst rectifier and thewinding of s-aid first stage and the other branch or which includes asecond rectifier and the winding of said second stage, current-limitingmeans, circuit means for connecting said parallel circuit and saidcurrent-limiting means in series circuit relationship with respect tosaid source, said first and said second rectifier being so poled as topermit, only during alternate halfcycles of the output ot said source,the flow of current from said source through said parallel circuit andsaid current-limiting means to thus gate the magnetic core member ofsaid first stage and reset the magnetic core member of said secondstage, means for resetting the ilux evel in the magnetic core member ofsaid first stage in accordance with a control signal during the otheralternate half-cycles of the output of said source, another parallelcircuit one branch of which includes a third rectifier and the windingof said second stage and the other branch of which includes a fourthrectifier and the winding or" said third stage, other current-limitingmeans, other circuit means for connecting said another parallel circuitand said other current-limiting means in series circuit relationshipwith respect to said source, said third and said fourth rectifier beingso poled as to permit, only during said other alternate half-cycles ofthe output ot said source, the ilow of current from said source throughsaid other current-limiting means and said another parallel circuit tothus gate the magnetic core member of said second stage and reset themagnetic core member of said third stage, further circuit meansconnected to said source for effecting a gating of the magnetic coremember oi said third stage during said alternate haltcycles oi theoutput of said source, and still other circuit means for connecting aload across the winding of said third stage.

3. ln a magnetic type delay line adapted to be connected to a source ofalternating voltage, the combination comprising, a iirst magnetic stageincluding a magnetic core member having a winding disposed in inductiverelationship therewith, a second magnetic stage including a magneticcore member having a winding disposed in inductive relationshiptherewith, a third magnetic stage including a magnetic core memberhaving a winding disposed in inductive relationship therewith, aparallel circuit, one branch of which includes a lirst rectifier and theWinding of said first stage and the other branch of which includes asecond rectifier and the winding of said second stage, current-limitingmeans, circuit means for connecting said parallel circuit and said curHrent-limiting means in series circuit relationship with respect to saidsource, said first and said second rectifier being so poled as topermit, only during alternate halfcycles of the output of said source,the flow of current from said source through said parallel circuit andsaid current-limiting means to thus gate the magnetic core member ofsaid first stage and reset the magnetic core member of said secondstage, other circuit means for so connecting a iirst load in parallelcircuit relationship with both branches of said parallel circuit thatcurrent ows through said load only during said alternate halicycles ofthe output of said source, means for resetting the flux level in themagnetic core member of said first stage in accordance with a controlsignal during the other alternate half-cycles of the output of saidsource, another parallel circuit one branch of which includes a thirdrectifier and the winding of said second stage and the other branch ofwhich includes a fourth rectier and the winding of said third stage,other current-limiting means, further circuit means for connecting saidanother parallel circuit and said other current-limiting means in seriescircuit relationship with respect to said source, said third and saidfourth rectiiers being so poled as to permit, only during said otheralternate halfcycles of the output of said source, the flow of currentfrom said source through said other current-limiting means and saidanother parallel circuit to thus gate the magnetic core member of saidsecond stage and reset the magnetic core member of said third stage,still other circuit means for so connecting a second load in parallelcircuit relationship with both branches of said another parallel circuitthat current flows through said second load only during said otheralternate half-cycles of the output of said source, still furthercircuit means connected to said source for eiecting a gating of themagnetic core member of said third stage during said alter natehalfecycles of the output of said source, and still other circuit meansfor so connecting a third load across the winding of said third stagethat current flows through l sait. third load only during said alternatehalf-cycles of the output of said source.

4. ln a magnetic type delay line ada"ted to be connected to a source ofalternating voltage, the combination comprising, a first magnetic stageincluding a magnetic core member having a winding disposed in inductiverelationship therewith, a second magnetic stage including a magneticcore member having a winding disposed in inductive relationshiptherewith, a third mag- Ac stage including a magnetic core member havinga winding disposed in inductive relationship therewith, a parallelcircuit, one branch of which includes a first rectier and the winding ofsaid first stage, and the other branch of which includes a secondrectifier and the winding of said second stage, current-limiting means,circuit means for connecting said parallel circuit and saidcurrent-limiting means in series circuit relationship with respect tosaid source, said rst and said second rectifiers being so poled as topermit, only during alternate half- -cycles of the output of saidsource, the flow of current .from said source through said parallelcircuit and said ycurrent-limiting means to thus gate the magnetic coremember of said first stage and reset the magnetic core member of saidsecond stage, further circuit means for connecting a biasing impedance,a third rectifier, and the winding of said first stage in series circuitrelationship with respect to said source so that current is permitted toflow from said source through said biasing impedance, said thirdrectifier, and the winding of said first stage only during the otheralternate half-cycles of the output of said source, still other circuitmeans, connected to the winding of said first stage, for effecting aresetting of the flux level in the magnetic core member of said firststage in accordance with a control signal during said other alternatinghalf-cycles of the output of said source, another parallel circuit onebranch of which includes a fourth rectifier and the winding of saidsecond stage and the other branch of which includes a fth rectifier andthe windinff of said third stage, other current-limiting sans, othercircuit means for connecting said another parallel circuit and saidother current-limiting means in series circuit relationship with respectto said source, said fourth and said fifth rectifiers beinfr so poled asto permit, only during said other alternate half-cycles of the output ofsaid source, the flow of current from said source through said othercurrent-limiting means and said another parallel circuit to thus gatethe magnetic core memy er of said second stage and reset the magneticcore member of said third stage, further circuit means connected to saidsource for effecting a gating of the magnetic core member of said thirdstage during said alternate half-cycles of the output of said source,and still other circuit means for connecting a load across the windingof said third stage.

5. ln a magnetic type delay line adapted to be connected to a source ofalternating voltage and adapted to Ybe controlled by a differentialcontrol signal, the combination comprising, a first magnetic stageincluding a first and a second magnetic core member each of which has awinding disposed in inductive relationship therewith, a second magneticstage including a third and a fourth magnetic core member each of whichhas a winding disposed in inductive relationship therewith, a thirdmagnetic stage including a fifth and a sixth magnetic =core member eachof which has a winding disposed in inductive relationship therewith, afirst parallel circuit on branch of which includes a first rectier andthe winding of said first magnetic core member and the other branch ofwhich includes a second rectifier and the winding of said third magneticcore member, a first current-limiting means, circuit means forconnecting said first parallel circuit and said first current-limitingmeans in series circuit relationship with respect to said source, saidfirst and said second rectier being .so poled as to permit, only Winglll'l@ half-@CIGS of the output of said source,

a flow of current from said source through said first parallel circuitand said first current-limiting means, to thus gate said first magneticcore member and reset Said third magnetic core member, a second parallelcircuit, one branch of which includes a third rectifier and the windingof said second magnetic core member and the other branch of whichincludes a fourth rectifier and the winding of said fourth magnetic coremember, a second current-limiting means, other circuit means forconnecting said second parallel circuit `and said second currentlii i.ng means in series circuit relationship with respect to said source,said third and said fourth rectiers being so poled as to permit, onlyduring said alternate halfcycles of the output of said source, the flowof current from said source through said second parallel circuit andsaid second current-limiting means to thus gate said second magneticcore member and reset said fourth magnetic core member, means forresetting the flux level in said first and in said second magnetic coremember in accordance with said differential control signal during theother alternate half-cycles of the output of said source, a thirdparallel circuit one branch of which includes a fifth rectifier and thewinding of said third magnetic core member and the other branch of whichincludes a sixth rectifier and the winding of said fifth magnetic coremember, a third current-limiting means, further circuit means forconnecting said third parallel circuit and said third current-limitingmeans in series circuit relationship with respect to said source, saidfifth and said sixth rectifier being so poled as to permit, only duringsaid other alternate half-cycles of the output of said source, a flow ofcurrent from said source through said third currentlimiting means andsaid third parallel circuit to thus gate said third magnetic core memberand reset said fifth magnetic core member, a fourth parallel circuit onebranch of which includes a seventh rectifier and the Winding of saidfourth magnetic core member and the other branch of which includes aneighth rectifier and the winding of said sixth magnetic core member, afourth current-limiting means, still further circuit means forconnecting said fourth parallel circuit and said fourth current-limitingmeans in series circuit relationship with respect to said source, saidseventh and said eighth rectifier being so poled as to permit, onlyduring said other alternate half-cycles of the output of said source,the flow of current from said source through said fourthcurrent-limiting means and said fourth parallel circuit to thus gatesaid fourth magnetic core member and reset said sixth magnetic coremember, still other circuit means connected to said source for eecting agating of said fifth and said sixth magnetic core member during saidalternate half-cycles of the output of said source, and still furthercircuit means for connecting a load across the combination of thewinding of said fifth magnetic core member and the winding of said sixthmagnetic core member,

6. ln a magnetic type delay line adapted to be connected to a source oflternating voltage and adapted to be controlled by a differentialcontrol signal, the comination comprising, a first magnetic stageincluding a rst and a second magnetic core member each of which has awinding disposed in inductive relationship therewith, a second magneticstage including a third and a fourth magnetic core member each of whichhas a winding disposed in inductive relationship therewith, a thirdmagnetic stage including a fifth and a sixth magnetic core member eachof which has a winding disposed in inductive relationship therewith, afirst parallel circuit one branch of which includes a first rectifierand the winding of said first magnetic core member and the other branchof which includes `a second rectier and the winding of said thirdmagnetic core member, a hrst current-limiting means, circuit means forconnecting said rst parallel circuit and said first current-limitingmeans in series circuit relationship with respect to said source, saidfirst 1?' and said second rectifiers being so poled as to permit, onlyduring alternate half-cycles of the output of said source, the flow ofcurrent from said source through said first parallel circuit and saidfirst current-limiting means, to thus gate said first magnetic coremember and reset said third magnetic core member, a second parallelcircuit one branch of which includes a third rectifier and the windingof said second magnetic core member and the other branch of whichincludes a fourth rectifier and the winding of said fourth magnetic coremember, a second current-limiting means, other circuit means forconnecting said second parallel circuit and said second currentdimitingmeans in series circuit relationship with respect to said source, saidthird and said fourth rectifier being so poled as to permit, only duringsaid alternate half-cycles of the output of said source, the fiow ofcurrent from said source through said second parallel circuit and saidsecond currentlimiting means to thus gate said second magnetic coremember and reset said fourth magnetic core member, further circuit meansfor connecting a first biasing impedance, a fifth rectifier, and theWinding of said first magnetic core member in series circuitrelationship with respect to said source, other circuit means forconnecting a second biasing impedance, a sixth rectifier, and theWinding of said second magnetic core member in series circuitrelationship with respect to said source so that current is permitted toffow from said source through said rst biasing impedance, said fifthrectifier and the Winding of said first magnetic core member and throughsaid second biasing impedance, said sixth rectifier and the Winding ofsaid second magnetic core member only during the other alternatehalf-cycles of the output of said source, further circuit meansconnected to the Winding of said first magnetic core member and to theWinding of said second magnetic core member for effecting a resetting ofsaid flux level in said first and said second magnetic core member inaccordance with said differential control signal during said otheralternate half-cycles of the output of said source, a first loadconnected to be energized in accordance with the combined voltage acrossthe Winding of said first magnetic core member and the Winding of saidsecond magnetic core member, a third parallel circuit, one branch ofwhich includes a seventh rectifier and the Winding of said thirdmagnetic core member and the other branch of which includes an eighthrectifier and the Winding of said fifth magnetic core member, thirdcurrent-limiting means, further circuit means for connecting said thirdparallel circuit and said third current-limiting means in series circuitrelationship with respect to said source, said seventh and said eighthrectifier being so poled as to permit, only during said other alternatehalf-cycles of the output of said source, a flow of current from saidsource through said third current-limiting means and said third parallelcircuit to thus gate said third magnetic core member and reset saidfifth magnetic core member, a fourth parallel circuit, one branch ofwhich includes a ninth rectifier and the Winding of said fourth magneticcore member and the other branch of which includes a tenth rectifier andthe Winding of said eighth magnetic core member, a fourthcurrent-limiting means, still further circuit means for connecting saidfourth parallel circuit and said fourth current-limiting means in seriescircuit relationship with respect to said source, said ninth and saidtenth rectifier being so poled as to permit, only during said otheralternate half-cycles of the output of said source, the fiow of currentfrom said source through said fourth currentlimiting means and saidfourth parallel circuit to thus gate said fourth magnetic core memberand reset said sixth magnetic core member, a second load connected to beenergized in accordance with the combined Voltage across the Winding ofs-aid third magnetic core member and the Winding of said fourth magneticcore member, still other circuit means connected to said source foreffecting a gating of said fifth and said sixth magnetic core membersduring said alternate half-cycles of the output of said source, andstill further circuit means for connecting a third load across thecombination of the winding of said fifth magnetic core member and thewinding of said sixth magnetic core member.

References Cited in the le of this patent UNlTED STATES PATENTS2,717,965 Rainey Sept. 13, 1955 2,747,109 Montner May 22, 1956 2,770,737Ramey Nov. 13, 1956 2,800,596 Bolie luly 23, 1957 2,875,398 StatemanFeb. 24, 1959 2,875,432 Markow Feb. 24, 1959

1. IN A MAGNETIC TYPE DELAY LINE ADAPTED TO BE CONNECTED TO A SOURCE OFALTERNATING VOLTAGE, THE COMBINATION COMPRISING, A FIRST MAGNETIC STAGEINCLUDING MAGNETIC CORE MEANS HAVING WINDING MEANS DISPOSED IN INDUCTIVERELATIONSHIP THEREWITH, A SECOND MAGNETIC STAGE INCLUDING MAGNETIC COREMEANS HAVING WINDING MEANS DISPOSED IN INDUCTIVE RELATIONSHIP THEREWITH,CIRCUIT MEANS FOR CONNECTING SAID WINDING MEANS OF SAID FIRST STAGE ANDSAID WINDING MEANS OF SAID SECOND STAGE IN PARALLEL CIRCUIT RELATIONSHIPWITH RESPECT TO ONE ANOTHER, CURRENTLIMITING MEANS, OTHER CIRCUIT MEANSFOR CONNECTING SAID PARALLEL CIRCUIT AND SAID CURRENT-LIMITING MEANS INSERIES CIRCUIT RELATIONSHIP WITH RESPECT TO SAID SOURCE, SO THAT CURRENTIS PERMITTED TO FLOW FROM SAID SOURCE THROUGH BOTH SAID WINDING MEANS OFSAID FIRST STAGE AND SAID WINDING MEANS OF SAID SECOND STAGE ONLY DURINGALTERNATE HALFCYCLES OF THE OUTPUT OF SAID SOURCE TO THUS GATE SAIDMAGNETIC CORE MEANS OF SAID FIRST STAGE AND RESET SAID MAGNETIC COREMEANS OF SAID SECOND STAGE, MEANS FOR RESETTING THE FLUX LEVEL IN SAIDMAGNETIC CORE MEANS OF SAID FIRST STAGE DURING THE OTHER ALTERNATEHALF-CYCLES OF THE OUTPUT OF SAID SOURCE, STILL OTHER CIRCUIT MEANSCONNECTED TO SAID SOURCE FOR EFFECTING A GATING OF SAID MAGNETIC COREMEANS OF SAID SECOND STAGE DURING SAID OTHER ALTERNATE HALF-CYCLES OFTHE OUTPUT OF SAID SOURCE, AND FURTHER CIRCUIT MEANS FOR CONNECTING ALOAD ACROSS SAID WINDING MEANS OF SAID SECOND STAGE.